2.07 Cytoskeleton Flashcards
Provides rigid physical support for certain parts of cells
Cytoskeleton
Extensive intracellular network of filamentous structures extending throughout the cytoplasm
Cytoskeleton
Physical support for certain parts of cells
Intracellular scaffolding
Function of cytoskeleton
Structural support
Cell motility
Cell regulation
Stabilize and balance opposing forces
Spherical/partially spherical shell structure of lattice shell based on a network of great circles on the surface of a sphere
Geodesic dome
Changes in cell location and limited movements of parts of the cell
Motility
Transmit mechanical signals that rearrange the nucleoli and other structures
Cell regulation
3 main types of cytoskeletal fibers
Microtubules
Microfilaments
Intermediate filaments
Types of cytoskeleton can be distinguished
Biochemically
By TEM
Contain alpha and beta tubulins
Grow or shrink as more tubulin molecules are needed or removed
Microtubules
Important for directing intracellular traffic
Motor molecules also carry vesicles or organelles to various destinations along monorails provided by cytoskeleton
Polarity
Function of microtubules
Mitosis spindle
Intracellular trafficking of vesicles
Cilia and flagella
Axoplasmic flow of materials along neuronal processes
Locomotory cells
Kinesins
Dyneins
Central structural supports in cilia and flagella
Microtubules
Move unicellular and small multicellular organisms by propelling water past the organism
Move fluid over a surface if anchored on large structures
Microtubules
Move more like oars with alternating power and recovery strokes
Cilia
Cilia generate force ______ to the axis of the cilia
Perpendicular
Undulatory movement
Flagella
Flagella
Eukaryotic
Undulating, wave-like, sinusoidal
Flagella
Prokaryotic
Rotatory
Only vertebrate cell that has flagella
Sperm
Both cilia and flagella have the same ________ arrangement
9+2 pattern
Bending of cilia and flagella is driven by the arms of a motor protein _____
Dynein
Drugs that inhibit microtubules
Anti - gout
Colchinine
Disrupts microtubules that facilitate the movement of WBC towards the site of inflammation to lessen inflammation
Colchicine
Drug that inhibit microtubules
Anti-fungal
Griseofulvin
Inhibit cellular division of fungus
Griseofulvin
Drug that inhibit microtubules
Chemotherapeutic agents
Stopping the mitosis of cancer cells
Vinbalstine
Paclitaxel
Rare generic disorder characterized by immobile cilia of the respiratory tract and the Fallopian tubes or sperm flagella
Kartagener Syndrome
Primary ciliary dyskinesia
Immobile cilia
Infertile
Dynein-deficient
Kartagener Syndrome
Primary ciliary dyskinesia
Forms microfilaments
Actin
Causes the bending of the cilia and flagella
Dynein
Monomeric globular
G-actin
At physiologic ionic strength and in the presence of magnesium, G-actin ____ noncovalently to form an insoluble double helical filament
Polymerizes
Has a pitch or repeating structure every 35.5 nm
F-actin
Function of microfilament
Resist tension
Form a 3D network
The shape of the microvilli in the intestinal cell are ____, anchored to a network of intermediate filaments
Supported by microfilaments
Thicker filaments composed of a motor protein, _____, interdigitate with the thinner actin fibers
Myosin
In other cells, less organized ____ cause localized contraction
Actin-myosin aggregates
Contracting belt of microfilaments divide the cytopalsm of animal cells during the cell division, also termed as ____
Cytokinesis
Localized contraction also drives ______, in which pseudopodia extend and contract through the reversible assembly and contraction of actin subunits into microfilaments
Amoeboid movement
Clathrin-mediated endocytosis, also referred to as _____, occurs at a membrane indentions where the triskeion-shaped protein clathrin accumulates
Receptor-mediated endocytosis
Filaments with an axial periodicity of 21 nm and a diameter of 8-10 nm that is intermediate between the other two
Intermediate filaments
More stable and permanent fixtures of the cytoskeleton than the other two classes
Intermediate filaments
Functions of intermediate filaments
Bearing tension
Reinforce cell shape and fix organelle location
Relatively stable components of the cytoskeleton
Rather deformable proteins that can be stretched severla times their initial length
Most types of IF are cytoplasmic, ____ are nuclear
Lamins
Cell-cell adhesion
Desmosomes
Cell-matrix adhesion
Hemidesmosomes
At the cell membrane, some keratins interact with ____ and ____ via adapter proteins
Desmosomes; hemidesmosomes
Distribution of IF
Lamins
Nuclear lamina
Distribution of IF
Keratins
Epithelial lining, hair, nail (Type I-acidic)